An atypical concentration or presence of substances in body fluids is indicative of the biological condition of the body. For example, the presence of HGC hormone in the blood of a human is characteristic of pregnancy. The presence of certain compounds or cells in the blood stream or in other body fluids characterizes pathologies. For example, an elevated level of sugar in the blood indicates an impaired function of certain organs. The presence of elevated concentrations of red blood cells in the gastrointestinal (GI) tract indicates different pathologies, depending on the location of the bleeding along the GI tract.
Early detection and identification of these biological or chemical substances is critical for correctly diagnosing and treating the various body conditions.
Medical detection kits are usually based on testing body fluid samples for the presence of a suspected substance i.e. In Vitro Diagnostics (IVD). This method of detection does not easily enable the localization or identification of the origin of an abnormally occurring substance. In many instances localizing an abnormally occurring substance in a body lumen greatly contributes to the identification of a pathology, and thus contributes to the facile treatment of the identified pathology. For example, bleeding in the stomach may indicate an ulcer while bleeding in the small intestine may indicate the presence of a tumor. The commonly used chemical methods for detecting blood in the GI tract do not enable the identification of the origin of the bleeding and further testing must be carried out to determine the type of pathology.
Detection of bleeding in the GI tract is possible by endoscope, however it is limited to the upper or lower gastrointestinal tract. Thus bleeding in the small intestine is not easily detected by endoscopy.
Parameters such as temperature, pH and pressure in the GI tract can be monitored by swallowable telemetry pills, such as the Heidelberg Capsule. For monitoring the gastric pH the Heidelberg Capsule, which is a miniaturized radio transmitter, comprises a pH measuring cell comprising two electrodes, one of which is in direct contact with the gastric fluid. The two electrodes are separated by a membrane permeable to ions (base battery), whereas pH changes alter the output voltages of the base battery which in turn effects the frequency of the capsule radio transmitter emission.